Constant sine bar



FIG. 1 is a top and left rear perspective view of a constant sine bar showing my new design;

FIG. 2 is a left side elevational view thereof, the right side being a mirror image thereto. The broken line showing of a roll-pin is environmental only and forms no part of the claimed design;

FIG. 3 is a top plan view thereof,

FIG. 4 is a bottom plan view thereof,

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a front elevational view thereof. 

The ornamental design for a constant sine bar, substantially as shown and described. 